Downhole tools generally refer to tools, apparatus, or components that are disposed or conveyed through a borehole penetrating the earth. These tools are generally used for geophysical exploration or production such as for hydrocarbons or geothermal energy or for carbon dioxide sequestration. Typically, the downhole tools have components that are required to be sealed together usually to either keep fluids in the component assembly from escaping or to keep harmful borehole fluids out.
Seals such as O-rings and gaskets for example may be used to seal such components together. Many of these seals are typically made of an elastomer having some elasticity. The elasticity allows the seal to be compressed yet provide some extrusion resistance that keeps the seal firmly planted against the sealing surfaces in order to provide sealing capability that may even accommodate some vibration. Unfortunately, temperatures downhole can be extremely high sometimes reaching 200° C. or even greater. These high temperatures can lead to the seals becoming soft and losing their ability to seal especially when subject to high vibrations in a while-drilling tool. To compensate for eventual temperature softening, extra hard O-rings or gaskets are sometimes used that may be too hard to sufficiently compress for a good seal at room temperature. Thus, there is a need for an elastomer with more gradual temperature softening than typical filled or unfilled elastomers.